Insulating glazing and the production method thereof

ABSTRACT

An insulating glazing unit including at least two glass sheets spaced apart by a gas-filled cavity, an insert that serves to keep the two glass sheets apart and that has an internal face facing the gas-filled cavity and an opposed external face, and a sealing with respect to the inside of the glazing unit. The insert includes a substantially flat strip that surrounds a first part of the perimeter of the glazing unit, being pressed by its internal face against the edges of the glass sheets and kept fastened by a fastener, and another strip that surrounds a second part of the perimeter of the glazing unit.

The subject of the invention is an insulating glazing unit and itsmanufacturing process.

One well-known type of insulating glazing unit comprises two glasssheets which are spaced apart by a cavity filled with gas, such as air,and which are kept apart and joined together by means of a spacer frameconsisting of hollow metal strips folded over or assembled by cornerpieces. The strips are provided with a molecular sieve whose function isespecially to absorb the water molecules that are trapped duringmanufacture of the glazing unit in the intermediate air cavity and thatwould be liable to condense in cold weather, which causes the appearanceof fogging.

To ensure that the glazing unit is sealed, the spacer frame isadhesively bonded to the glass sheets by an elastomer bead of the butylrubber type, applied directly to the strips by extrusion through anozzle. Each corner of the spacer frame is also provided at a cornerpiece with butyl rubber. Once the glazing has been assembled, theelastomer sealing bead has a function of temporarily providingmechanical retention of the glass sheets. Finally, a crosslinkablesealing mastic, of the polysulfide or polyurethane type, is injectedinto the peripheral groove bounded by the two glass sheets and thespacer frame, thereby completing the mechanical assembly of the glasssheets. The main function of the butyl rubber is to seal the inside ofthe glazing unit with respect to water vapor, whereas the mastic sealsagainst liquid water and solvents.

The manufacture of this glazing unit requires several differentmaterials, including the strips, the corner pieces, the molecular sieveand the organic seals, these materials not being assembled in one andthe same operation.

One drawback associated with such a manufacturing process is that ofstoring the materials. In order to be operational in respect of any neworder for insulating glazing units, many batches of each material mustbe available, which does not contribute to simple and rapid managementas regards the positioning and storage of these materials.

Furthermore, the present number of materials to be assembled involvesseveral mounting operations which, although automated, are carried outone after another, which appreciably disadvantages the manufacturingtime. Some of these operations also involve interruptions in themanufacturing line, these short periods of lost time possibly furtherdisadvantaging productivity.

In addition, the regeneration of the molecular sieve with which theinside of the hollow strips is provided is impossible with theinsulating glazing units known at the present time, as it involves theirdestruction.

The object of the invention is therefore to obviate these drawbacks byproviding an insulating glazing unit whose choice of materials makes itpossible to facilitate the management of their manufacturing flow, tosimplify the mounting operations and to restore the glazing unit withoutdestroying it, especially by replacing the granular molecular sieveand/or reintroducing gas.

According to the invention, the insulating glazing unit, which comprisesat least two glass sheets spaced apart by a gas-filled cavity, an insertthat serves to keep the two glass sheets apart and has an internal facefacing the gas-filled cavity and an opposed external face, and means forsealing with respect to the inside of said glazing unit, ischaracterized in that the insert comprises a substantially flat stripwhich surrounds a first part of the perimeter of the glazing unit, beingpressed via its internal face against the edges of the glass sheets andkept fastened by fastening means, and another strip which surrounds asecond part of the perimeter of the glazing unit.

This type of strip and its arrangement on the edges of the glazing unithas especially the advantage of increasing the visibility through theglazing unit in those parts of its periphery having as insert only thesubstantially flat strip.

There may be partial or even complete overlap of said first and secondparts of the perimeter of the glazing unit, provided that theconventional spacing and sealing functions of the insert are fulfilled.In many cases, the second part of the perimeter occupied by said otherstrip does not represent the entire perimeter. This is because, if theother strip is hollow, the major benefit of the invention lies in takingadvantage of the extreme ease of bonding and debonding the substantiallyflat strip, especially so as to be able to gain access to the inside ofthe hollow strip in order to replace the desiccating molecular sievethat it contains; now, this accessibility is optimal when the hollowstrip occupies part, but not all, of the perimeter of the glazing unit,for example the lower horizontal side, or only a fraction of a straightside. The rebonding of the flat strip after it has been debonded posesno problem with many choices of standard materials.

The term “other strip” is understood within the context of the inventionto mean a strip that is not essentially flat, hollow or solid, ofsquare, rectangular or more complex cross section, having for exampleone side of length corresponding substantially to the thickness of thegas-filled cavity.

The glazing unit of the invention comprises at least two glass sheets,mainly three or more, spaced apart, each being either a monolithic glasssheet or a laminate of glass and plastic sheets.

In accordance with two embodiments that are not mutually exclusive:

-   -   said other strip is pressed via its internal face against the        edges of the glass sheets, either directly or with        interposition, for example, of said substantially flat strip;    -   said other strip is at least partly located between the glass        sheets.

In both cases, the other strip may be adhesively bonded to the glasssheets, whether to their edges or to their internal surfaces. However,it is also possible that such bonding is not effected, for example, inconfiguration such as:

-   -   another strip pressed against the edges of the glass sheets and        completely enveloped by the flat strip itself, adhesively bonded        to the glass; and    -   another strip, completely between the glass sheets, on the lower        horizontal side, bearing by gravity on the internal face of the        flat strip, or with clamping between the two glass sheets.

Advantageously, the other strip comprises at least a part which liesoutside the space bounded by the glass sheets and has a shape suitablefor fitting and/or fastening the glazing unit in the opening for whichit is intended. It is thus conceivable for this outer part of the otherstrip to form a tongue over the entire length of the strip and for thistongue to be able to fit closely into a groove formed in the frame ofthe opening, thereby making superfluous the subsequent fastening, bynailing or an equivalent method, of a beading, called a glazing bead, tothis perimeter part of the glazing unit.

Preferably, the insert possesses properties whereby it seals againstgases and dust and against liquid water.

The sealing means of the substantially flat strip are placed at least onthe external face or at least on the internal face of the insert. In thelatter case, the external face of the substantially flat stripadvantageously has irregularities capable of ensuring the fitting and/orcentering and/or fastening of the glazing in the opening for which it isintended. These irregularities may consist of longitudinal striationssuch as those obtained by extrusion of a thermoplastic or a similarprocess. In this regard, reference may be made to the application EP-0745 750 A1 which describes (FIGS. 7 and 8) stepped striations with oneside inclined and the other straight, arranged along inclined ramps anddesigned to fasten the glazing unit in its frame, with simultaneouscentering, by simple pressing. Striations of this type fall perfectlywithin the present embodiment.

The sealing means of the substantially flat strip may consist of acoating made of metal, preferably stainless steel or aluminum, which hasa thickness of between 2 and 50 μm.

The substantially flat strip may be made entirely of metal.

When the strip is made of plastic, it is provided with a metal coatingin order to constitute the gas and water-vapor sealing means asindicated above.

This coating may be just as well on the outer face as on the inner faceof the gas-filled cavity side. There are advantages in arranging itpreferably on the inner face, namely a smaller thickness will benecessary, since there will be no need to withstand the external shocksor scratching, the thermal bridge around the periphery of the glazingunit will be thinner, its bonding, especially if it is made of aluminum,to the glass is perfectly controlled whatever the plastic used for thestrip, and finally it may make it easier to make electrical connectionto the electrical elements provided inside the glazing unit.

According to one feature, the insert has a linear buckling strength ofat least 400 N/m. To ensure this strength, the flat strip must have athickness of at least 0.1 mm when it consists entirely of stainlesssteel, of at least 0.15 mm when it is entirely made of aluminum and atleast 0.25 when it is made of a thermo-plastic reinforced withreinforcing fibers.

Advantageously, the means for fastening the insert to the glazing unitare impermeable to water and they consist of an adhesive which has atear strength of at least 0.45 MPa.

According to another feature, the free ends of the substantially flatstrip are joined together in order to surround all or part of theglazing unit so that one of the ends overlaps the other, or one end ofsaid other strip, supplementary sealing means being provided in order toseal off lateral sections left open by the overlap.

As a variant, to surround the entire glazing unit, the free ends of thesubstantially flat strip are of complementary shapes suitable formutually cooperating in order for them to be assembled as an abutment.An adhesive tape or adhesive impermeable to gases and to water vaporwill preferably be applied to the abutment region.

The insulating glazing unit may be of complex shape, in particular withcurved parts, to which the flat insert is perfectly suited as it isable, through its flexibility, to easily follow the curves of theglazing unit.

According to another feature, either or both of the faces of the inserthas/have functional elements structured by forming or materiallyattached.

Thus, it is possible for the strip to be shaped in very precise shapes.Before it is fitted, the strip may be formed by rolling or any othersuitable means for incorporating various elements for functionalpurposes. As an example, it is possible to structure the faces of thestrip with studs, dimples or bumps, placed in discrete points orcontinuously, arranged for example in two parallel bands, or in astaggered fashion, or by providing sharp edges in the corners, such aspunches, serrations or prescoring.

The studs may especially serve as retention elements for fastening thecross members installed in the gas-filled cavity, these cross membershaving a decorative function.

If these studs are placed toward the inside of the glazing unit and inat least two parallel bands, they may serve as elements for guiding andfitting at least one additional glass sheet for the manufacture of atriple, or even quadruple, glazing unit. However, they may also serve aselements for holding a glass sheet in place which, by thus resting onthese elements, allows communication between the various air-filledcavities of the glazing unit. These elements, if their functionality istoward the outside of the glazing unit, may also make it easier to mountby insertion, fit, lock or install the glazing unit in the rebate of thewindow or with adjacent walls or glazing units, or else these elementsmay constitute a path for cooperation with a rail, for a sliding door.

Of course, it is conceivable to add further elements to the strip byother means, depending on the nature of material on the strip, byadhesive bonding, soldering, welding or riveting without the integrityof the strip being thereby modified, even though it may bere-established if it is modified. In addition, by grasping on additionalparts it will be possible to form inserts that further improve therigidity and inertia of the strip for assembling the glazing, or elsecontributing to installing it, especially mounting it in the rebate.

There may also additions of further materials by plastic studs or by theextrusion of profiled lips or grooves for sealing or for decoration.

Apart from these additions, it is quite conceivable beforehand to applyanticorrosion treatment or a paint or a decorative lacquer to the strip,and also to stamp or print any marking or information for the purpose,for example, of providing traceability of the glazing unit manufactured.

The insert, of substantially flat shape, may have recesses or doublewalls that may constitute or house functionality's, for examplebreathing tubes (i.e. tubes permitting the pressures between the insideand the outside of the glazing unit to be balanced without convection).

The insert of the invention advantageously includes one or more of thefollowing functionalities:

-   -   it contains a desiccant, especially in a recess incorporated        into the shape of the insert or attached to the insert;    -   it includes control, mechanical-transmission or        electrical-connection means (electrical wires, conducting        elements for heating the edges of the glazing unit, printed        circuits), the conductors being led out, for example, in the        abutment region;    -   it incorporates a venetian blind installed in the gas-filled        cavity; and    -   it incorporates a means of measuring the moisture content in the        gas-filled cavity, so as to predict the moment when it is        necessary to restore the glazing unit, by removing, washing and        refitting it and by regenerating the desiccant.

It is particularly advantageous, thanks to the invention, to associate asaid substantially flat strip with three of the four sides of theglazing unit, to install one of the aforementioned functionalities viathe free side of the glazing unit and then to adhesively bond a saidsubstantially flat strip to the latter.

In one embodiment, the insert has at least one hole so as to be able,for example, to affix a desiccant cartridge, or a gas cartridge so as tofill the space between the glass sheets with gas, and also to be able toundertake pressure balancing when the glazing unit has been manufacturedin a location where atmospheric pressure is different from that of thepoint of delivery, or else the hole or holes may allow controlledcirculation of air between the glass sheets so as to constitute abreathing glazing unit very useful, for example, for an oven door. Thishole may be produced in the substantially flat strip, or else in theother strip, or in both, the two holes being advantageously, in thelatter case, facing each other. The hole may or may not be in directcommunication with the gas-filled cavity (for example when there is anend section of hollow strip, in which sealing is provided by overlapwith a substantially flat strip). The hole may or may not be a throughhole; thus, it may result only from the local absence of the impermeablelayer, made of aluminum or other material, but not from the underlying,possibly gas-permeable, layer.

This hole may be obtained by any suitable piercing means or by anelement attached to the strip provided with a punch, by piercing thestrip at the indicated point, or for example by a preshaped impressionon the strip, or by the precise positioning of the attached element byvirtue of locating bumps shaped beforehand on the strip, as explainedabove. The piercing impression may, for example, be of the type providedin commercial aluminum drinks cans; once piercing has taken place, theportion of material pushed back remains attached to the strip.

It the hole has been produced for the injection of gas, it is thenadvisable to seal it up again, for example with a gas-impermeable foil,which is mechanically fastened to the strip by various means, such aswith the use of a suitable sealing adhesive.

Thus, the tape may be adhesively bonded via one of its faces to thatface of the foil intended to be applied against the holed strip. Thetape has, on its opposite face, a nonstick protective film which allows,during application of the foil against the strip, to modify the positionof said foil so as to place it correctly in the desired location. Atongue is provided laterally to the strip and can be pulled so as toremove the protective film in order to expose the adhesive which willensure that the foil is bonded to the strip.

The invention also covers a particular glazing unit in which the edgesof said two glass sheets are at least partly offset with respect to eachother. It is conceivable that only one side of one of the two sheetsextends beyond the corresponding side of the other of the two sheets,the offset space being occupied by said other strip, over the entirelength of the side. It is also possible for one of said two glass sheetsto be a laminate whose sheet oriented toward the outside of the glazingunit is of larger dimensions than the other constituents of thelaminate, adhesively bonded to the edge of which constituents on the onehand, and to the edge of the other of said two glass sheets on the otherhand, is a said substantially flat strip.

Another particular insulating glazing unit according to the invention isdistinguished by the fact that at least one of said two glass sheets hasa through-hole and that the edges of this hole are considered as formingpart of said first part of the perimeter of the glazing unit, asubstantially flat strip being pressed against and adhesively bonded ina sealed manner to these edges. If the through-hole is a disc, the flatstrip is shaped in the form of a tube in which are provided, as the casemay be, means for fastening the glazing unit to a building structure orthe like.

Finally, the fact that the insert is placed on the edges of the glasssheets means that the internal peripheral surface of the glass sheetswhich are close to the edges is left free, whereas in the prior art thissurface is occupied by the insert. It is thus possible to use this freesurface for fixing elements, such as decorative cross members, forexample by adhesive bonding. When the glazing unit is incorporated intoa window frame, the fastening is invisible because it lies within therebate of the window, away from daylight.

A first manufacturing process of the invention is characterized in that:

-   -   said other strip, provided as the case may be with its means for        fastening to the glazing unit, and the two glass sheets, kept        parallel and spaced apart, are assembled;    -   the internal face of the substantially flat strip provided with        the fastening means is placed against the edges of the glass        sheets and, as the case may be, on the external face of the        other strip;    -   during the step of placing the substantially flat strip,        pressure means are applied almost instantaneously on the        external face of the latter so as to ensure that it adheres to        the edges of the glass sheets and, as the case may be, to the        other strip; and    -   the two ends of the substantially flat strip are securelly        joined, either one end to the other, or each of the ends to one        end of the other strip.

According to one feature, the substantially flat strip before being putinto place is in the form of a wound tape intended to be unwound,stretched and cut to the desired length, whereas the adhesive typefastening means are deposited by injection means onto the tape beingstretched.

Advantageously, the desiccant is deposited onto the tape beingstretched, during application of the fastening means.

According to another feature, the substantially flat strip is put intoplace by pressing down on it at a starting point against the edges of afirst side of the glazing unit, the surrounding operation taking placefrom this starting point and the tape being placed over the corners ofthe glazing unit in the case of a substantially flat strip based on athermoplastic by preheating its external face so as to help it to bebent around the corners and match their contour perfectly.

Preferably, the starting point is located midway along one side of theglazing unit so as to apply and compress the substantially flat stripsimultaneously in the two opposite directions, thereby making itpossible to save manufacturing time.

As a variant, the starting point may be located instead at a corner ofthe glazing unit.

In an alternative method of surrounding the glazing unit, thesubstantially flat strip is put into place by applying two tapes andpressing down on them at two starting points using delivery andcompression means, and the surrounding operation takes place from thesestarting points by translational movements of the glazing unit and/or ofthe delivery means. This variant, combined with the strip of theinvention, very advantageously makes it possible to provide a glazingunit of complex shape, in particular one with curved parts.

In practice, all the operations of manufacturing the glazing unit may becarried out in a chamber filled with the gas that has to be containedwithin the glazing unit. However, as a variant, it is possible toenvision a gas feed device inserted between the two glass sheets, inorder to deliver gas, while the glazing unit is undergoing thesurrounding operation, and said device is removed just before the end ofthe surrounding operation.

A second manufacturing process of the invention is characterized inthat:

-   -   the two glass sheets are kept parallel and spaced apart;    -   the internal face of the substantially flat strip, provided with        the means for fastening against the edges of the glass sheets,        is placed around the entire perimeter of the glazing unit;    -   while the substantially flat strip is being put in place,        pressure means are applied almost instantaneously on its        external face so as to ensure that it adheres to the edges of        the glass sheets;    -   after the entire glazing unit has been surrounded, the two ends        of the substantially flat strip are securely joined together;    -   a hole in the substantially flat strip is sealed off by means of        a said other strip, the hole possibly being drilled by the        coming-together of the substantially flat strip and of the other        strip shaped for this purpose with a self-boring means, this        operation requiring the use of means for making said other strip        adhere to the substantially flat strip, such as an adhesive        tape, optionally combined with an injected adhesive.

Further features and advantages of the invention will become apparent onreading the description which follows and in conjunction with theappended drawings in which:

FIG. 1 a is a sectional view of the insulating glazing unit according tothe invention in which the hollow strip does not appear;

FIG. 1 b is a partial schematic sectional representation of aninsulating glazing unit according to the invention, in which the hollowstrip is adhesively bonded directly to the edges of the glass sheets;

FIG. 1 c is a partial schematic sectional representation of aninsulating glazing unit according to the invention, in which the hollowstrip is adhesively bonded to the edges of the glass sheets via theinterposition of a substantially flat strip;

FIG. 1 d is a partial schematic sectional representation of aninsulating glazing unit according to the invention, in which the hollowstrip is adhesively bonded between the glass sheets;

FIG. 2 illustrates a schematic vertical view of the device for applyingthe substantially flat strip to the glass sheets;

FIG. 3 shows FIG. 2 during one step of the manufacturing process,

FIG. 4 is an enlarged view of the join between the two free ends of theflat strip according to the invention after completely surrounding theglazing unit;

FIGS. 5 a to 5 c illustrate an alternative method of surrounding theglazing unit, in a configuration in which the hollow strip is entirelylocated within the space bounded by the glass sheets; and

FIG. 6 shows a curve plotting the ratio of the maximum deflection of astandard glazing unit of the prior art to the maximum deflection of aglazing unit of the invention for a given force as a function of thethickness of the air cavity.

FIG. 1 a illustrates a simple insulating glazing unit 1 obtained by amanufacturing process that will be described below with regard to itsdevice shown in FIG. 2.

The glazing unit 1 comprises two glass sheets 10 and 11 spaced apart bya gas-filled cavity 12, an insert 2 which serves to keep the two glasssheets spaced apart and has the function of ensuring mechanicalretention of the entire glazing unit, and sealing means 3 intended toseal the glazing unit against liquid water, solvents and water vapor.

The insert 2 is in the form of a substantially flat strip approximately1 mm in thickness and substantially parallelepipedal in cross section.Advantageously, this strip has a low mechanical inertia, that is to saythat it can be easily wound up with a small winding radius of 10 cm forexample.

The strip surrounds the perimeter of the glazing unit. It is placed inthe manner of a tape on the edges 10 a and 11 a of the glass sheets andguarantees mechanical assembly of the glazing unit by virtue of thefastening means 4 which ensure total adhesion to the glass.

The strip is strong enough to provide the function of mechanicallykeeping the two glass sheets spaced apart. Its strength is defined bythe very nature of its constituent material, the linear bucklingstrength of which must be at least 400 N/m.

Moreover, the nature of the material of said strip is also chosen sothat, during the process of manufacturing the glazing unit, the stripcan present sufficient flexibility for the operation of surrounding theglass edges, in particular when bordering the corners, to be carriedout.

In a first embodiment, the insert is made entirely of metal, thematerial chosen being preferably stainless steel or aluminum. During theprocess, the corners are bordered by bending using machines well knownto those skilled in the art in the conversion of metallic material.

In order to guarantee a minimum linear buckling strength of 400 N/m, theinsert must have a thickness of at least 0.1 mm in the case of stainlesssteel and 0.15 mm in the case of aluminum.

In a second and preferred embodiment of the invention, the insert 2 isbased on a plastic, which may or may not be reinforced with chopped orcontinuous reinforcing fibers. Thus, one material may be styreneacrylonitrile (SAN) combined with chopped glass fibers, this productbeing sold, for example, under the name LURAN® by BASF, or elsepolypropylene reinforced with continuous glass fibers, this productbeing sold under the name TWINTEX® by Vetrotex.

It is also possible to produce the insert from a combination ofmaterials such as plastic and metal in order to form, for example, aninsert with a thickness of plastic solidly combined with a thickness ofmetal.

It should be noted, in the case of a plastic which is a thermoplastic,the operation of bordering corners of the glazing unit, by bending thematerial after it has been softened, is carried out more easily thanwith an entirely metallic material.

Moreover, with the use of plastic, provision may very advantageously bemade for the desiccant to be intrinsically incorporated, partly orcompletely, into the strip, this being impossible with metal. Thedesiccant may be a molecular sieve such as powdered zeolite, theproportion of which may be up to 20% by weight or about 10% by volume.The amount of desiccant depends on the lifetime that it is wished toassign on the glazing unit.

Finally, since the plastic is less heat conducting than the metal, thethermal insulation of the entire glazing unit is but better when theglazing unit is exposed, for example, to strong sunlight.

As regards the addition of glass fibers to the plastic, this results ina thermal expansion coefficient of the material which is much lower thanthat of a pure plastic and which becomes close to the coefficient of theglass. This generates, during a thermal variation of the gas-filledcavity, a lower shear force on the fastening means 4.

To ensure a linear strength of 400 N/m, the insert 2 has a thickness ofat least 0.2 mm when it consists of a thermoplastic and reinforcingfibers.

The width of the insert 2 is tailored to the total thickness of theglazing unit, which may be a multiple glazing unit comprising severalglass sheets spaced apart by gas-filled cavities. Advantageously, withthe insert of the invention it is required to know only the total widthof the glazing unit and not the separating distances of the glasssheets. This is because the separating distances for a multiple glazingunit may vary, which necessarily means that, in the case of the use ofinserts according to those of the prior art, having to have available,for manufacturing the glazing unit, several inserts for the differentseparations and different widths of inserts depending on the separatingdistances.

For the entire glazing unit, it is therefore necessary to simply have,according to the invention, one insert or strip having a single widthcorresponding to the total width of the glazing unit, whatever thenumber of internal isolating separations of this spacing unit and thewidth of the separations.

It has been demonstrated that the glazing unit of the invention with itsinsert placed on the edges of the glass sheets does not lose out interms of strength but, on the contrary, the strength is further improvedcompared with a standard glazing unit of the prior art which has itsinsert placed between the internal faces of the glass sheets.

The ratio of the deflection of the glazing unit of the invention to thatof a standard glazing unit has been calculated as a function of thethickness of the air cavity for glass sheets having the same surfacearea, the same glass thickness and the same air cavity thickness. Forthis purpose, a given force is applied to each of the glazing units, themaximum deflection of each glazing unit is then measured and then theratio of the deflections is calculated. This ratio, being equal to thedeflection of the standard glazing unit divided by the deflection of theglazing unit of the invention, is always greater than 1 on account ofthe better resistance to bending and therefore the better strength ofthe glazing unit of the invention.

FIG. 6 illustrates this ratio as a function of the air cavity, theinsert in question for the insulating glazing unit of the inventionbeing a 0.5 mm aluminum strip. It may be seen that the ratio is alwaysgreater than 1 and is, for example, 1.5 for a 12 mm air cavity.

According to the invention, the insert or the strip 2 has an internalface 20 and an opposed external face 21, the internal face 20 beingintended to be pressed and held in place, via its edges in the case of asingle insulating glazing unit, against the edges 10 a and 11 a of theglass sheets by virtue of the fastening means 4.

The internal face 20 of the strip possesses, in its central part 22facing the gas-filled cavity 12, the properties of those of a desiccantwhose purpose is to absorb the water molecules that may be trappedwithin the gas-filled cavity. These desiccating properties may resultfrom the nature of the material of the insert, the very composition ofwhich incorporates a molecular sieve. As a variant, the desiccatingelement may instead be obtained by depositing a molecular sieve on thecentral part 22 before the insert is placed on the edges of the glazingunit, as will be seen in the rest of the description.

The edges of the internal face 20 are covered with an adhesive, whichconstitutes the fastening means 4.

The adhesive is of the cement type; it is impermeable to gases and towater vapor. Tests carried out in accordance with United States StandardASTM 96-63T on specimens of adhesive 1.5 mm in thickness have shown thatan adhesive having a water vapor permeability coefficient of 35 g/24h·m², like that of silicon, is suitable. Of course, an adhesive having apermeability coefficient of 4 g/24 h·m², like polyurethane, or evenlower, is more suitable since, sealing being further improved, a smalleramount of desiccant then has to be provided.

The adhesive must also withstand debonding by liquid water, byultraviolet radiation and by pulling forces that may be exertedperpendicularly to the faces of the glazing unit, usually called shearstresses, and by the pulling forces exerted parallel to the force of theweight of the glazing unit. A satisfactory adhesive must have a tearstrength of 0.45 MPa.

It will also be judicious to tailor the nature of the adhesive to theoperating environments of the glazing unit; thus, the adhesive will haveto have, for example, a temperature withstand capability sufficient forthe application of the glazing unit to the door of a domestic electricoven.

Preferably, the adhesive possesses rapid bonding properties, bonding inthe order of a few seconds; it is an adhesive whose setting takes placeby chemical reaction, whether or not activated by heat or pressure, orelse takes place by cooling if the adhesive consists of a hot-meltmaterial, for example one based on a polyurethane that can crosslink incontact with the moisture of the air.

The external face 21 of the reinforced plastic insert is covered with ametallic protective coating 21 a of the aluminum or stainless steel foiltype with a thickness of, for example, between 2 and 50 μm, this coatingconstituting the sealing means 3. Apart from its sealing role, the foil,particularly when it is made of stainless steel, provides the strip witheffective protection against abrasion, for example when handling it ortransporting it. Finally, the strip favors heat exchange with thethermoplastic when the manufacturing process involves softening thelatter.

As a variant, the metal coating 21 a could be wide enough to cover theexternal face 21 and be folded down along the edges of the internal face20.

The numbers given above regarding the thickness of the insert, dependingon the nature of the material or materials used, are given for a linearbuckling strength of 400 N/m, which is a conventional value for glazingunits of the most standard size, namely 1.20 m by 0.50 m. However, toextend the use to glazing units of larger size and/or glazing unitsexposed to extreme stressing conditions, it will be preferred to designglazing units whose insert is capable of withstanding a force of 5700 Nper linear meter. To achieve such a buckling strength, we give below atable indicating the safety factor calculated with respect to the 5700N/m reference as a function of the corresponding thicknesses to be givento the insert of the invention depending on the type of material. SafetyStyrene acrylonitrile Stainless Factor (SAN) Aluminum steel 1 0.50 mm0.25 mm 0.20 mm 3 0.75 mm 0.40 mm 0.30 mm 4.5 0.90 mm 0.45 mm 0.35 mm

The integration of the hollow strip into the insulating glazing unit ofthe invention is illustrated in figures 1 b to 1 d.

Referring to FIG. 1 b, the hollow strip 30 is adhesively bonded byfastening means 5 to the edges of the glass sheets 10 and 11 Thus, theinternal face 20 of the insert is a boundary of the gas-filled cavity12, so that the desiccating molecular sieve (not shown) contained in thehollow profile is active with respect to the gas-filled cavity viacommunications 31—holes, pores, etc.—made in the internal face 20 ifnecessary, these communications 31 with the gas-filled cavity areexposed by locally removing a possible sealing layer with which thestrip 30 would be provided. The dimensions of the communications 31 aresmaller than those of the desiccant, which frequently is in the form ofgranules, so as to retain them in the hollow strip 30.

The fastening means 5 guarantee the required sealing between thegas-filled cavity 12 and the outside atmosphere.

The hollow strip is placed over all or part of a straight side of theinsulating glazing unit, in a single section or in several sectionshaving a length, for example, of 10 to 15 cm. Optionally, the hollowstrip may be blocked off with a hot-melt material having a low moisturetransmission, such as a polyurethane.

A substantially flat section (not shown in FIG. 1 b) is adhesivelybonded to each of the two end sections of the hollow strip 30, that itthus blocks off in a sealed manner, possibly in combination with theaforementioned hot-melt material having a low moisture transmission.

The flat strip 2 (see FIG. 1 a) includes sealing means, consisting asdescribed above of an aluminum foil 3, which may be oriented toward theinside of the glazing unit, the adhesive 4 being chosen to bond thealuminum to the hollow profile 30 and also to the edges of the glasssheets. This orientation of the sealing means 3 has the advantage ofallowing the external face of the flat strip 2, for example made ofplastic, to be formed with striations, for fastening the glazing unit asdescribed in application EP-745 750 A1, especially by extrusion.

The situation of the hollow strip 30, at least partly to the outside ofthe space bounded by the glass sheets, allows it to be used in mountingthe glazing unit by insertion into a groove formed in the frame of theopening, without an additional step of fastening a cover strip beingnecessary. Such is also the advantage afforded by the embodiment shownin FIG. 1 c, to which reference will now be made.

According to this embodiment, a substantially flat strip 2 provided withits outwardly oriented sealing means 3 surrounds the entire perimeter ofthe insulating glazing unit, being bonded by the adhesive 4 to the edgesof the glass sheets. The flat strip 2 has a hole 6 which, for example,may be cut after the flat strip has been bonded to the glass sheets andpossibly after a certain period of use of the glazing unit resultingtherefrom. A hollow strip 30 has therefore in this case beensubsequently bonded to the flat strip 2 by the adhesive 5 The molecularsieve contained in the hollow of the strip 30 is active with respect tothe gas-filled cavity 12, with which it communicates via the pores orholes 31 made in the internal wall 20 of the strip 30 and via the hole 6

The hollow strip 30 may in this case also be blocked off at its endswith a thermoplastic having a low moisture transmission. Supplementarysealing means (not shown) are opportunely used between the flat strip 2and the hollow strip 30, namely adhesive tape or injection of suitablematerials in order to seal off the lateral open overlap sections (seeabove). These supplementary means are removable, so that regeneration ofthe molecular sieve of the strip 30, possible after a long period of useof several years, is particularly simplified by the arrangements of theinvention.

FIG. 1 d shows a variant in which a hollow strip 30 is fitted entirelywithin the space bounded by two glass sheets 10 and 11 of an insulatingglazing unit by adhesive bonding using a material 5′ capable ofproviding the required sealing between the gas-filled cavity and theoutside atmosphere, but only over part of the periphery of the glazingunit, preferably over part or all of a straight side of the glazingunit. A substantially flat strip (not shown) overlaps and is adhesivelybonded to at least each of the two end sections of the hollow strip 30so as to provide, or at least contribute to, the required sealingbetween the recess of the hollow strip 30 and the outside atmosphere.Thus, all that is required is to debond a sufficient part of the flatstrip 2 in order to expose one end of the hollow strip 30 so as toreplace the spent desiccant that it contains and then to rebond it.

The manufacturing process will now be described with reference to thepreferred embodiment of the invention, using a substantially flat stripbased on a reinforced thermoplastic. This description excludes theintegration into the insulating glazing unit of the hollow strip, saidintegration being described above; this integration is carried outbefore the flat strip is assembled (the embodiments shown in FIG. 1 band 1 d) or thereafter (the embodiment shown in FIG. 1 c).

The glass sheets 10 and 11 are conveyed on edge by standard means andtaken into a chamber that may contain the gas to be introduced into theglazing unit.

The glass sheets 10 and 11 are held, with the desired spacing, by meansof suckers placed on the external faces of the glazing unit andcontrolled by pneumatic cylinders.

FIG. 2 illustrates schematically the device for manufacturing theglazing unit enclosed in the chamber 2.

A reel 50 constitutes the magazine of the strip 2 which is unwound andstretched, using a stretching device (not shown), in the form of a tapewhich is cut to a length equivalent to the perimeter of the glazingunit, the width of the tape corresponding to the total thickness of theglazing unit.

Once the strip has been made out flat, the adhesive 4 is deposited usinginjection means 51, such as a nozzle, on the internal face 20 of thetape, intended to be applied against the edge of the glazing unit. Inthis case, the tape includes the desiccant inherent in its internalface, the desiccant having been incorporated in the form of powder orgranules into the reinforced thermoplastic during manufacture of thestrip.

However, when the desiccant is to be added after the strip has beenmanufactured, it will be preferred to put the desiccant and the adhesivein place during one and the same operation using three injectionnozzles, namely two lateral nozzles, directed toward the edges of thetape in order to deposit adhesive for the purpose of being opposite theedges of the glazing unit, and one central nozzle injecting thedesiccant onto the central part 22 of the tape for the purpose of beingopposite the gas-filled cavity.

It is also possible to envision an adhesive which has been depositedduring manufacture of the strip and which is protected until it is used,corresponding in this case to when the strip is applied to the glazingunit.

At least one press roller 54, controlled by an articulated arm (notshown) applies the tape 2 and presses it against the edge of the glazingunit 1 over its entire perimeter. To save time in the surroundingoperation, it will be preferable to provide two rolls 54, which will bedriven in the two opposed directions and will border the two halves ofthe perimeter simultaneously.

Heating means 55, such as hot-wire resistors, are provided in order toheat the strip before it is bent and applied at the corners of theglazing unit.

The operation of the device is as follows.

The two glass sheets 10, 11 held spaced apart are fixedly positioned inthe center of the chamber C.

Beneath the glazing unit, the strip or tape 2, including the desiccantand the sealing means 4, is unwound, stretched and cut.

The two press rollers 54 are brought into contact with the tape in orderto apply the latter at the midpoint of the lower horizontal side of theglazing unit. Once the tape has been pressed against the edge of theglazing unit, the bordering operation is started at the midpoint, thusensuring that the tape is under tension.

The rolls 54 then move in opposite directions toward the bottom leftcorner 13 and bottom right corner 14 of the glazing unit.

Before the press rollers 54 start to go around the two corners 13 and14, they are momentarily stopped while the hot wires 55 are put intoplace downstream of the rollers, close to and facing the metal foil 21 aof the strip in order to heat the thermoplastic intended to be appliedagainst the corners (FIG. 3).

After the strip has been softened, the press rollers 54 are again putinto operation in order to bend the strip and border the corners 13 and14 of the glazing unit correctly. The rollers then continue to travelaround the perimeter of the glazing unit up to the top corners 15 and 16of the glazing unit, when the operation of heating the strip is repeatedby means of hot wires 55.

Once the top corners of the glazing unit have been surrounded, the pressrollers 54 finish by bordering the last side of the glazing unit. Onapproaching the middle of this last side, one of the rollers is stoppedwhile the other roller continues to compress the strip until the freeend 23 of the strip associated with this operating roller overlaps theother end 24 of the strip put into place (FIG. 4). The surroundingoperation is then complete and the press rollers 54 are disengaged fromthe glazing unit.

To strengthen the fastening of the two ends 23 and 24 of the tape andabove all to seal the two open lateral sections 25 of the tape which aredue to the overlapping of the ends, supplementary sealing means, such asadhesive, are injected so as to close off these said sections 25.

An alternative method (not illustrated) of joining the two ends of thetape together may consist not in overlapping them but in abutting them,one against the other, when they have complementary shapes designed tomutually cooperate in the manner of a tenon and a mortice. To ensurecomplete sealing, adhesive or adhesive tape, impermeable to gases and towater vapor, such as a stainless steel adhesive tape, will be added tothe abutment region.

Although the two ends of the tape have been joined together whether byoverlap or by abutment, on one of the sides of the glazing unit, it isalso possible as a variant to make this joint at a corner of the glazingunit.

Moreover, in alternative method of implementing the process, provisionmay be made for there to be two heads 56 a, 56 b for delivering the tape2, respectively a stationary head and a head that can move vertically,each head associated with a press roller 54, the glazing unit being ableto be moved in horizontal translation.

Referring to FIG. 5 a, the glazing unit, having entered the chamber C(not illustrated here) is placed between position {circle over (1)}corresponding to the front of the glazing unit and position {circle over(2)} corresponding to the rear of the glazing unit. At the start, themovable head 56 b begins from a bottom corner of the glazing unitcorresponding to position {circle over (1)} and is driven upward so asto follow the front vertical side of the glazing unit. Once the head 56b has reached the top corner, it pivots through 90° and is stopped, thetwo heads then facing one another. The glazing unit is then movedtranslationally from the left to the right, that is to say the rear ofthe glazing unit goes from position {circle over (2)} to position{circle over (1)} so that the horizontal sides of the glazing unit aresimultaneously surrounded by each of the heads respectively (FIG. 5 b).Finally, the rear of the glazing unit is stopped in position {circleover (1)} and the vertical side is surrounded by the movable head thathas pivoted through 90° at the upper corner of the glazing unit in orderto descend down to the bottom corner (FIG. 5 c). The two tapes are thenfastened together in the bottom corners of the glazing unit by overlapor by abutment.

This combination of the translational movement of the glazing unit andthat of at least one tape delivery head makes it possible to save timein surrounding the glazing unit.

Furthermore, this combination of movements and the use of the strip ofthe injection makes it possible to surround glazing units of complexshapes, having for example curved edges with concave and/or convexshapes.

An alternative method of filling with the gas that has to be containedin the glazing unit may be envisioned. Instead of having to have agas-filled chamber, a gas feed device is provided, such as a hose whichis inserted between the two glass sheets and delivers gas as the edgesof the glazing unit are being surrounded and sealed off. The device isremoved just before the last side of the glazing unit is closed off.

The strip of the invention has a flat and parallelepipedal overallshape, however, alternative embodiments are possible. For example, itmay be envisioned to provide the internal face 20 of the strip, on theopposite side to that having the metal coating, with centering andpositioning means such as longitudinal projections or lugs uniformlydistributed along two longitudinal lines separated by a width equivalentto the separation of the two glass sheets so that the strip is suitablyguided and positioned against the edge of the glazing unit, theprojections or lugs being inserted into the glazing unit and beingpressed against the internal walls.

1-32 (Canceled). 33: An insulating glazing unit, comprising: two glasssheets spaced apart by a gas-filled cavity; an insert that serves tokeep the two glass sheets apart and that has an internal face facing thegas-filled cavity and an opposed external face; and means for sealingwith respect to an inside of the glazing unit, wherein the insertcomprises a substantially flat first strip that surrounds a first partof a perimeter of the glazing unit, being pressed by its internal faceagainst edges of the glass sheets and kept fastened by fastening means,and a second strip that surrounds a second part of the perimeter of theglazing unit. 34: The insulating glazing unit as claimed in claim 33,wherein said second strip is pressed by its internal face against theedges of the glass sheets. 35: The insulating glazing unit as claimed inclaim 33, wherein said second strip is at least partly located betweenthe glass sheets. 36: The glazing unit as claimed in claim 33, whereinsaid second strip comprises at least a part that lies outside a spacebounded by the glass sheets and that has a shape configured to at leastone of fit and fasten the glazing unit in an opening for which theglazing unit is intended. 37: The insulating glazing unit as claimed inclaim 33, wherein the insert possesses properties configured to sealagainst gases and dust and against liquid water. 38: The insulatingglazing unit as claimed in claim 33, wherein the means for sealing ofsaid substantially flat first strip are placed at least on the externalface of the insert. 39: The insulating glazing unit according to claim33, wherein the means for sealing of said substantially flat first stripare placed at least on the internal face of the insert. 40: Theinsulating glazing unit as claimed in claim 39, wherein the externalface of said substantially flat first strip has irregularitiesconfigured to at least one of set, center, and fasten the glazing unitin an opening for which the glazing unit is intended. 41: The glazingunit as claimed in claim 40, wherein said irregularities includelongitudinal striations obtained by extrusions of a thermoplastic. 42:The glazing unit as claimed in claim 33, wherein at least one of thefaces of the insert has longitudinal elements structured by forming orsecurely attached. 43: The glazing unit as claimed in claim 33, whereinpart of the insert includes a painting or lacquering anticorrosiontreatment or a printing-based marking treatment. 44: The insulatingglazing unit as claimed in claim 33, wherein the means for sealing ofthe substantially flat first strip includes a metal coating. 45: Theinsulating glazing unit as claimed in claim 34, wherein saidsubstantially flat first strip is made entirely of metal, or ofstainless steel with a thickness of at least 0.10 mm, or of aluminumwith a thickness of at least 0.15 mm, or is made of a thermoplastic thatincludes continuous or chopped reinforcing glass fibers to have athickness of at least 0.2 mm. 46: The insulating glazing unit accordingto claim 33, wherein said substantially flat first strip has a linearbuckling strength of at least 400 N/m. 47: The insulating glazing unitas claimed in claim 33, wherein the fastening means are impermeable towater vapor and to gases. 48: The insulating glazing unit as claimed inclaim 33, wherein the fastening means includes an adhesive. 49: Theinsulating glazing unit as claimed in claim 48, wherein the adhesive hasa tear strength of at least 0.45 MPa. 50: The insulating glazing unit asclaimed in claim 33, wherein said substantially flat first strip has twofree ends joined together to surround all or part of the glazing unit sothat one of the ends overlaps the other, or one end of said secondstrip, and further comprising supplementary sealing means for sealingoff lateral sections left open by the overlap. 51: The insulatingglazing unit according to claim 33, wherein said substantially firstflat strip has two free ends of complementary shapes configured tomutually cooperate to result in their abutment so as to go around anentirety of the glazing unit. 52: The insulating glazing unit as claimedin claim 51, further comprising an adhesive tape or adhesive,impermeable to gases and to water vapor, applied to a region of theabutment. 53: The insulating glazing unit as claimed in claim 33,wherein the glazing unit has a complex shape, with curved parts. 54: Theinsulating glazing unit as claimed in claim 33, wherein the insertcontains a desiccant and/or includes control, electrical-connection andmechanical-transmission means and/or incorporates a venetian blindinstalled in the gas-filled cavity and/or means for measuring moisturecontent and/or serves for fastening cross members installed in thegas-filled cavity. 55: The insulating glazing unit as claimed in claim33, wherein the insert includes at least one hole. 56: The insulatingglazing unit as claimed in claim 33, wherein the edges of the two glasssheets are at least partly offset with respect to each other. 57: Theinsulating glazing unit as claimed in claim 33, wherein at least one ofsaid two glass sheets includes a through-hole and edges of thisthrough-hole form part of said first part of the perimeter of theglazing unit, a substantially flat third strip being pressed against andadhesively bonded in a leaktight manner to the edges of thethrough-hole. 58: A process for manufacturing an insulating glazing unitas claimed in claim 33, wherein: said second strip is provided with thefastening means for fastening to the glazing unit and is joined to thetwo glass sheets, which are kept parallel and spaced apart, to beassembled; the internal face of the substantially flat first stripprovided with the fastening means is placed against the edges of theglass sheets and, on an external face of the second strip; duringplacing the substantially flat first strip, pressure means are appliedalmost instantaneously on the external face of the substantially flatfirst strip to ensure that it adheres to the edges of the glass sheetsand to the second strip; and the two ends of the substantially flatfirst strip are securely joined, either one end to the other, or each ofthe ends to one end of the second strip. 59: The process formanufacturing an insulating glazing unit as claimed in claim 58, whereinthe substantially flat first strip before being put into place is in aform of a wound tape configured to be unwound, stretched, and cut to adesired length, whereas the fastening means is deposited by injectiononto the tape being stretched. 60: The process for manufacturing aninsulating glazing unit as claimed in claim 59, wherein a desiccant isdeposited onto the tape being stretched, during application of thefastening means. 61: The process for manufacturing an insulating glazingunit as claimed in claim 58, wherein a gas feed device is provided,inserted between the two glass sheets, to deliver gas, while the glazingunit is undergoing the surrounding operation, and said gas feed deviceis removed just before an end of the surrounding operation. 62: Theprocess for manufacturing an insulating glazing unit as claimed claim33, wherein: the two glass sheets are kept parallel and spaced apart;the internal face of the substantially flat first strip, provided withthe means for fastening it against the edges of the glass sheets, isplaced around an entire perimeter of the glazing unit; while thesubstantially flat strip is being put in place, pressure means areapplied almost instantaneously on its external face to ensure that itadheres to the edges of the glass sheets; after the entire glazing unithas been surrounded, the two ends of the substantially flat strip aresecurely joined together; a hole in the substantially flat strip issealed off by said second strip, the hole being drilled bycoming-together of the substantially flat strip and the second stripshaped for this purpose. 63: A strip configured to form the insert of aninsulating glazing unit, wherein the strip is substantially flat, withan approximately parallelepipedal shape, and has functional elementsstructured by forming or securely attached. 64: The strip as claimed inclaim 63, including, on one of its main faces, means for centering andpositioning the insert on the glazing unit.